Current status (as of end of 2020) of marine alien species in Turkey.

The 2020's update of marine alien species list from Turkey yielded a total of 539 species belonging to 18 taxonomic groups, 404 of which have become established in the region and 135 species are casual. A total of 185 new alien species have been added to the list since the previous update of 2011. The present compilation includes reports of an ascidian species (Rhodosoma turcicum) new to the marine fauna of Turkey and range extensions of six species. Among the established species, 105 species have invasive characters at least in one zoogeographic region, comprising 19% of all alien species. Mollusca ranked first in terms of the number of species (123 species), followed by Foraminifera (91 species), Pisces (80 species) and Arthropoda (79 species). The number of alien species found in seas surrounding Turkey ranged from 28 (Black Sea) to 413 (Levantine Sea). The vectoral importance of the Suez Canal diminishes when moving from south to north, accounting for 72% of species introductions in the Levantine Sea vs. only 11% of species introductions in the Black Sea. Most alien species on the coasts of Turkey were originated from the Red Sea (58%), due to the proximity of the country to the Suez Canal. Shipping activities transported 39% of alien species, mainly from the Indo-Pacific area (20%) and the Atlantic Ocean (10%). Misidentified species (such as Pterois volitans, Trachurus declivis, etc.) and species those classified as questionable or cryptogenic were omitted from the list based on new data gathered in the last decade and expert judgements. The documented impacts of invasive species on socio-economy, biodiversity and human health in the last decade as well as the legislation and management backgrounds against alien species in Turkey are presented.

Mangelia (Gastropoda, Conoidea) species of the Turkish coasts with description of Mangelia vanaartseni sp. nov.

The present study addresses the distribution of Mangelia species along the Turkish coasts. The studied material was collected during the last two decades from different habitats (soft and hard bottoms, and macrophyte beds) at depths ranging from the intertidal zone to 1000 m at stations along the Levantine, Aegean and Black Seas coasts of Turkey, and from the Sea of Marmara. Among the analyzed benthic material, 311 living specimens and 114 shells belonging to 18 species of the genus Mangelia were obtained. Mangelia vanaartseni is described as a new species. Among the recognized species, Mangelia unifasciata (Deshayes, 1835) is the most widely distributed species in the study area, while Mangelia secreta (Van Aartsen Fehr-de Wal 1978), Mangelia pallaryi (Nordsieck 1977) and Mangelia striolata Risso 1826 were the rarest ones. Mangelia costata (Pennant 1777) and Mangelia costulata Risso 1826 were found to occur at depths up to 200 m, while most other species occurred at shallower depths. Along with the description of the new species, ecological and distributional characteristics and figures of specimens are also provided.